Nanofluidic memristor based on aao film and preparation method thereof

Abstract

The application discloses a kind of nanofluid memristor based on AAO film and preparation method thereof, specifically: first copper electrode is arranged on glass substrate, PDMS liquid pool is arranged on first copper electrode, AAO film and CuSO4 electrolyte are arranged inside PDMS liquid pool, and second copper electrode is arranged on the top of PDMS liquid pool.The preparation method is: first copper electrode is placed in the central position of glass substrate, and gelatinous PDMS is dropped to the front end of first copper electrode;Punching is carried out on the solidified PDMS layer using a puncher, and a PDMS liquid pool is obtained;AAO film is transferred to the PDMS liquid pool, so that the lower surface of the AAO film is attached to the front end of the first copper electrode, and CuSO4 electrolyte is filled in the PDMS liquid pool;Second copper electrode is placed on the upper end of the PDMS liquid pool, and the PDMS liquid pool is sealed by covering the PDMS liquid pool with PDMS.The memristor in the application has the advantages of small working voltage, low power consumption, simple preparation and good stability.

Description

Technical Field

[0001] This invention relates to the field of micro-nano electronic device technology, and in particular to a nanofluidic memristor based on AAO thin film and its fabrication method. Background Technology

[0002] Current digital computers are based on the traditional von Neumann architecture, which is characterized by the separation of storage units and computing units. This separation hinders the rapid exchange and efficient processing of large amounts of data, thus forming the von Neumann bottleneck.

[0003] In biology, research has shown that the human brain consumes only about 20W of power, is compact, and computationally efficient. In biological neural networks, neurons not only store information but also process and transmit it. Therefore, researchers hope to mimic the biological brain to develop in-memory computing architectures—neuromorphic computing—to achieve low-power computing methods.

[0004] The advent of memristor devices has accelerated the development of neuromorphic computing. Memristors, the fourth type of fundamental circuit element, were first proposed by Shao-Tang Tsai in 1971 to represent the relationship between electric charge and magnetic flux. The resistance of a memristor changes with the amount of charge that has passed through it, thus exhibiting memory properties, similar to the function of biological synapses. After HP Labs first fabricated a physical memristor in 2008, researchers attempted to use it to simulate synaptic plasticity to realize the synaptic function in neural networks. The non-volatile nature of this device also means that the weights of memristor-based artificial neural networks can be maintained even after power is turned off. Memristors demonstrate excellent performance in high-density integration and fast response, providing crucial support for improving the performance of neuromorphic computing.

[0005] Currently, traditional solid-state memristors are often used as synapses in artificial neural networks, enabling various neural network functions. However, the power consumption of solid-state memristors still falls short of that of biological neurons. Solid-state memristors mostly rely on electron transport in a solid medium, while in living organisms, synapses utilize ions to transport information in a liquid environment. Compared to electrons, ions are more diverse, have better biocompatibility, and stronger resistance to electromagnetic interference. Therefore, researchers have begun to attempt to simulate synapses and build memristors that utilize ion transport at the nanoscale—namely, nanofluidic memristors. Currently, nanofluidic memristors based on different mechanisms such as ion adsorption, interface movement, and channel switching have been realized, but these nanofluidic memristors still face challenges such as high operating voltage, high power consumption, and complex fabrication. Summary of the Invention

[0006] The purpose of this invention is to provide a nanofluidic memristor based on AAO thin film with low operating voltage, low power consumption, simple fabrication, and good stability, as well as its fabrication method.

[0007] The technical solution to achieve the purpose of this invention is: a nanofluidic memristor based on AAO thin film, comprising a glass substrate, a PDMS reservoir, an AAO thin film, a CuSO4 electrolyte, a first copper electrode, and a second copper electrode;

[0008] The glass substrate is the base plate of the memristor. A first copper electrode is disposed on the glass substrate. A PDMS reservoir is disposed on the first copper electrode. An AAO thin film is disposed in the PDMS reservoir and a CuSO4 electrolyte is contained therein. A second copper electrode is disposed on top of the PDMS reservoir. The first copper electrode, the AAO thin film, and the second copper electrode are connected in sequence.

[0009] The AAO film contains multiple parallel nanochannels of a set size but with inconsistent pore sizes at both ends, forming a nanochannel array. The two ends of the nanochannel array are respectively connected to the first copper electrode and the second copper electrode.

[0010] The copper ions in the CuSO4 electrolyte can undergo a solid-liquid reaction with the inner wall of the nanochannel in the AAO film, allowing the copper ions to be adsorbed onto the inner wall of the nanochannel.

[0011] The first and second copper electrodes are used to apply voltage to both ends of the nanochannel array in the AAO thin film. Under the drive of the electric field, copper ions in the CuSO4 electrolyte enter or leave the nanochannel array. Through the adsorption and desorption of copper ions by the inner wall of the nanochannel, the conductivity of the nanochannel array changes. This change is lagging behind the voltage change applied by the electrodes, thereby generating the memristor effect and realizing a nanofluid memristor based on the AAO thin film.

[0012] Furthermore, the thickness of the glass substrate ranges from 1 to 2 mm, the length ranges from 7 to 8 cm, and the width ranges from 2 to 3 cm.

[0013] Furthermore, the PDMS storage tank is made of polydimethylsiloxane, i.e., PDMS material.

[0014] Furthermore, the AAO film is made of anodized aluminum oxide, i.e., AAO material.

[0015] Furthermore, the density of nanochannels in the AAO film is 280 pore·μm. -2 The average distance between the centers of two adjacent nanochannels is 60 nm.

[0016] The geometry of a single nanochannel is asymmetrical, with inconsistent pore sizes at both ends. The average pore sizes at both ends range from 20 to 30 nm and from 40 to 50 nm, respectively, while the depth ranges from 50 to 60 μm, and the cross-section is bullet-shaped.

[0017] Furthermore, the number of PDMS storage tanks is one, the shape is cubic, the length ranges from 5 to 20 mm, the width ranges from 5 to 15 mm, and the depth ranges from 1 to 3 mm.

[0018] Furthermore, the length of the first copper electrode and the second copper electrode are both 20-40 mm, the width is both 1-5 mm, and the thickness is both 0.1-0.2 mm, and they are placed on the lower end face and the upper end face of the PDMS storage tank, respectively.

[0019] A method for fabricating a nanofluidic memristor based on an AAO thin film includes the following steps:

[0020] Step 1: Place the first copper electrode in the center of the glass substrate, drop gel PDMS onto the front end of the first copper electrode, and heat the glass substrate to accelerate the curing of PDMS.

[0021] Step 2: Use a punch to make holes in the cured PDMS layer to obtain a PDMS storage tank;

[0022] Step 3: Transfer the AAO film, cut to the set size and containing the nanochannel array, into the PDMS reservoir, so that the lower surface of the AAO film is attached to the front end of the first copper electrode on the glass substrate, and then fill the PDMS reservoir with CuSO4 electrolyte.

[0023] Step 4: Place the second copper electrode on the upper end of the PDMS reservoir, and then cover and seal the PDMS reservoir with PDMS.

[0024] Further, in step 1, a first copper electrode is placed at the center of the glass substrate, and gel-like PDMS is drop-coated onto the front end of the first copper electrode. The glass substrate is then heated to accelerate the curing of the PDMS, as detailed below:

[0025] Step 1.1: Select the central position of the glass substrate, attach one end of the first copper electrode to the central position, and define this end as the front end and the other end as the rear end. The first copper electrode is horizontally attached to the glass substrate along the direction from the front end to the rear end.

[0026] Step 1.2: Mix 0.5 mL of PDMS precursor and curing agent thoroughly at a weight ratio of 10:1 to form gel PDMS. Let the gel PDMS stand to remove air bubbles. Then, drop the gel PDMS onto the central part of the glass substrate and let the PDMS spread naturally to cover the front end of the first copper electrode near the center of the glass substrate.

[0027] Step 1.3: Place the glass substrate on a heating stage and heat it at 120°C for 2 hours to accelerate the curing of the gel PDMS and finally form a cured PDMS layer.

[0028] Furthermore, in step 4, a second copper electrode is placed at the upper end of the PDMS storage tank, and then the PDMS storage tank is covered and sealed using PDMS, as detailed below:

[0029] Step 4.1: Take another glass substrate, mix 0.5 mL of PDMS precursor and curing agent at a weight ratio of 10:1 to form a gel PDMS. Let the gel PDMS stand to remove air bubbles, and then drop the gel PDMS onto the center of the glass substrate and let the PDMS spread naturally.

[0030] Step 4.2: Place the glass substrate on a heating stage and heat it to accelerate the curing of the gel-like PDMS, eventually forming a cured PDMS layer;

[0031] Step 4.3: Peel off the cured PDMS layer from the glass substrate, align it and cover the top of the PDMS reservoir, and use PDMS to cover and seal the PDMS reservoir to prevent the CuSO4 electrolyte in the PDMS reservoir from evaporating.

[0032] Compared with the prior art, the significant advantages of this invention are: (1) It uses a copper electrode with a low standard electrode potential, so the working voltage of the device is very small, about 20mV. When working, the energy consumption of each nanochannel in the device is about 0.11fJ / spike, while the average energy consumption of a single biological synapse when working is about 10 to 100fJ / spike. The energy consumption of the device described in this invention is even lower than that of a biological synapse; (2) The AAO film has a high surface area, chemical inertness and controllable pore size. In solution, the nanochannel surface will form abundant hydroxyl groups, which have a good absorption effect on heavy metal ions; (3) The overall preparation process does not require complex equipment, and the preparation method is simple and low in cost. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of a nanofluidic memristor based on an AAO thin film according to the present invention.

[0034] Figure 2 This is a scanning electron microscope characterization image of the AAO nanochannel in an embodiment of the present invention.

[0035] Figure 3 This is a current-voltage (IV) data curve of the nanofluidic memristor in the embodiment of the present invention.

[0036] Figure 4 This is an IV cycle data curve during the operation of the nanofluid memristor in this embodiment of the invention.

[0037] Figure 5 This is a schematic diagram illustrating the working principle of the nanofluidic memristor in this embodiment of the invention.

[0038] Figure 6 This is a graph showing the pairwise pulse enhancement factor (PPF) and pairwise pulse suppression factor (PPD) data during the operation of the nanofluidic memristor in this embodiment of the invention.

[0039] Figure 7 This is a graph showing the short-term enhanced STF and short-term suppressed STD data during the operation of the nanofluidic memristor in this embodiment of the invention. Detailed Implementation

[0040] Combination Figure 1 The present invention discloses a nanofluidic memristor based on an AAO thin film, comprising a glass substrate, a PDMS reservoir, an AAO thin film, a CuSO4 electrolyte, a first copper electrode, and a second copper electrode.

[0041] The glass substrate is the base plate of the memristor. A first copper electrode is disposed on the glass substrate. A PDMS reservoir is disposed on the first copper electrode. An AAO thin film is disposed in the PDMS reservoir and a CuSO4 electrolyte is contained therein. A second copper electrode is disposed on top of the PDMS reservoir. The first copper electrode, the AAO thin film, and the second copper electrode are connected in sequence.

[0042] The AAO film contains multiple parallel nanochannels of a specific size but with inconsistent pore sizes at both ends, forming a nanochannel array. The two ends of the nanochannel array are respectively connected to the first copper electrode and the second copper electrode.

[0043] The copper ions in the CuSO4 electrolyte can undergo a solid-liquid reaction with the inner wall of the nanochannel in the AAO film, allowing the copper ions to be adsorbed onto the inner wall of the nanochannel.

[0044] The first and second copper electrodes are used to apply voltage to both ends of the nanochannel array in the AAO thin film. Under the drive of the electric field, copper ions in the CuSO4 electrolyte enter or leave the nanochannel array. Through the adsorption and desorption of copper ions by the inner wall of the nanochannel, the conductivity of the nanochannel array changes. This change is lagging behind the voltage change applied by the electrodes, thereby generating the memristor effect and realizing a nanofluid memristor based on the AAO thin film.

[0045] As a specific example, the thickness of the glass substrate is on the order of millimeters, and its length and width are on the order of centimeters. Preferably, the thickness of the glass substrate ranges from 1 to 2 mm, the length ranges from 7 to 8 cm, and the width ranges from 2 to 3 cm.

[0046] As a specific example, the PDMS storage tank is made of polydimethylsiloxane, i.e., PDMS material.

[0047] As a specific example, the AAO film is made of anodized aluminum oxide, i.e., AAO material.

[0048] As a specific example, the AAO film contains hundreds of nanochannels per square micrometer, and the average distance between the centers of two adjacent nanochannels is on the order of nanometers.

[0049] The individual nanochannels have asymmetrical geometry, with inconsistent pore sizes at both ends. The average pore size at both ends is on the nanometer scale, the depth is on the micrometer scale, and the cross-section is bullet-shaped. Preferably, the density of nanochannels in the AAO film is 280 pores·μm. -2 The average distance between the centers of two adjacent nanochannels is 60 nm; the geometry of a single nanochannel is asymmetrical, with inconsistent pore sizes at both ends, with average pore sizes ranging from 20 to 30 nm and 40 to 50 nm respectively, a depth range of 50 to 60 μm, and a bullet-shaped cross-section.

[0050] As a specific example, the PDMS storage tank is a single cubic tank, with its length, width, and depth all in the millimeter range. Preferably, the PDMS storage tank is a single cubic tank, with a length ranging from 5 to 20 mm, a width ranging from 5 to 15 mm, and a depth ranging from 1 to 3 mm.

[0051] As a specific example, the length, width, and thickness of the first and second copper electrodes are all on the order of millimeters, and they are placed on the lower and upper end faces of the PDMS storage tank, respectively. Preferably, the length of the first and second copper electrodes is in the range of 20–40 mm, the width is in the range of 1–5 mm, and the thickness is in the range of 0.1–0.2 mm, and they are placed on the lower and upper end faces of the PDMS storage tank, respectively.

[0052] This invention also provides a method for fabricating a nanofluidic memristor based on an AAO thin film, comprising the following steps:

[0053] Step 1: Place the first copper electrode in the center of the glass substrate, drop-coat gel-like PDMS onto the front end of the first copper electrode, and heat the glass substrate to accelerate the curing of PDMS, as detailed below:

[0054] Step 1.1: Select the central position of the glass substrate, attach one end of the first copper electrode to the central position, and define this end as the front end and the other end as the rear end. The first copper electrode is horizontally attached to the glass substrate along the direction from the front end to the rear end.

[0055] Step 1.2: Mix 0.5 mL of PDMS precursor and curing agent thoroughly at a weight ratio of 10:1 to form gel PDMS. Let the gel PDMS stand for a period of time to remove air bubbles. Then, drop the gel PDMS onto the central part of the glass substrate and let the PDMS spread naturally to cover the front end of the first copper electrode.

[0056] Step 1.3: Place the glass substrate on a heating stage and heat it at 120°C for 2 hours to accelerate the curing of the gel PDMS and finally form a cured PDMS layer.

[0057] Step 2: Use a punch to make holes in the cured PDMS layer to obtain a PDMS storage tank;

[0058] Step 3: Transfer the AAO film, cut to a specific size and containing a nanochannel array, into the PDMS reservoir, so that its lower surface is attached to the front end of the first copper electrode on the glass substrate, and then fill the PDMS reservoir with CuSO4 electrolyte.

[0059] Step 4: Place the second copper electrode on top of the PDMS reservoir, and then cover and seal the PDMS reservoir with PDMS, as follows:

[0060] Step 4.1: Take another glass substrate, mix 0.5 mL of PDMS precursor and curing agent at a weight ratio of 10:1 to form a gel PDMS. Let the gel PDMS stand for a period of time to remove air bubbles, and then drop the gel PDMS onto the central part of the glass substrate and wait for the PDMS to spread naturally.

[0061] Step 4.2: Place the glass substrate on a heating stage and heat it to accelerate the curing of the gel-like PDMS, eventually forming a cured PDMS layer;

[0062] Step 4.3: Peel off the cured PDMS layer from the glass substrate, align it and cover the top of the PDMS reservoir, and use PDMS to cover and seal the PDMS reservoir to prevent the CuSO4 electrolyte in the PDMS reservoir from evaporating.

[0063] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0064] Example

[0065] Combination Figure 1 This embodiment provides a glass substrate, a PDMS reservoir, an AAO thin film, a CuSO4 electrolyte, a first copper electrode, and a second copper electrode.

[0066] The glass substrate is the base plate of the memristor. A first copper electrode is disposed on the glass substrate. A PDMS reservoir is disposed on the first copper electrode. An AAO thin film is disposed in the PDMS reservoir and a CuSO4 electrolyte is contained therein. A second copper electrode is disposed on top of the PDMS reservoir. The first copper electrode, the AAO thin film, and the second copper electrode are connected in sequence.

[0067] The AAO film contains multiple parallel nanochannels of a specific size but with inconsistent pore sizes at both ends, forming a nanochannel array. The two ends of the nanochannel array are respectively connected to the first copper electrode and the second copper electrode.

[0068] The copper ions in the CuSO4 electrolyte can undergo a solid-liquid reaction with the inner wall of the nanochannel in the AAO film, allowing the copper ions to be adsorbed onto the inner wall of the nanochannel.

[0069] The first and second copper electrodes are used to apply voltage to both ends of the nanochannel array in the AAO thin film. Under the drive of the electric field, copper ions in the CuSO4 electrolyte enter or leave the nanochannel array. Through the adsorption and desorption of copper ions by the inner wall of the nanochannel, the conductivity of the nanochannel array changes. This change is lagging behind the voltage change applied by the electrodes, thereby generating the memristor effect and realizing a nanofluid memristor based on the AAO thin film.

[0070] As a specific example, the glass substrate has a thickness of 1 mm, a length of 7.6 cm, and a width of 2.5 cm.

[0071] As a specific example, the PDMS storage tank is made of polydimethylsiloxane, i.e., PDMS material.

[0072] As a specific example, the AAO film is made of anodized aluminum oxide, i.e., AAO material.

[0073] As a specific example, the density of nanochannels in the AAO film is 280 pores·μm. -2 The average distance between the centers of two adjacent nanochannels is 60 nm.

[0074] The individual nanochannels have asymmetrical geometry, with inconsistent pore sizes at both ends. The average pore sizes at the two ends are 24 nm and 40 nm, respectively, with a depth of 56 μm and a bullet-shaped cross-section.

[0075] As a specific example, the storage tank is a single cubic tank with an average length of 10 mm, an average width of 7 mm, and an average depth of 2 mm; the electrolyte injected into the storage tank is a CuSO4 solution with a concentration of 1 M.

[0076] As a specific example, the first copper electrode and the second copper electrode are 0.1 mm thick, 30 mm long, and 2 mm wide, and are placed on the lower and upper ends of the PDMS storage tank, respectively.

[0077] A method for fabricating a nanofluidic memristor based on an AAO thin film includes the following steps:

[0078] Step 1: Place the first copper electrode in the center of the glass substrate, drop-coat gel-like PDMS onto the front end of the first copper electrode, and heat the glass substrate to accelerate the curing of PDMS, as detailed below:

[0079] Step 1.1: Place the first copper electrode on the glass substrate, with its front end positioned at the very center of the glass substrate;

[0080] Step 1.2: Mix 0.5 mL of PDMS precursor and curing agent thoroughly at a weight ratio of 10:1 to form gel PDMS. Let the gel PDMS stand for a period of time to remove air bubbles. Then, drop the gel PDMS onto the central part of the glass substrate and let the PDMS spread naturally to cover the front end of the first copper electrode.

[0081] Step 1.3: Place the glass substrate on a heating stage and heat it at 120°C for 2 hours to accelerate the curing of the gel PDMS and finally form a cured PDMS layer.

[0082] Step 2: Use a punch to make holes in the cured PDMS layer to obtain a PDMS storage tank;

[0083] Step 3: Transfer the AAO film, cut to a specific size and containing a nanochannel array, into the PDMS reservoir, so that its lower surface is attached to the front end of the first copper electrode on the glass substrate, and then fill the PDMS reservoir with CuSO4 electrolyte.

[0084] Step 4: Place the second copper electrode 1 mm horizontally from the first copper electrode on the upper surface of the PDMS reservoir. Then, cover and seal the PDMS reservoir with PDMS, as follows:

[0085] Step 4.1: Take another glass substrate, mix 0.5 mL of PDMS precursor and curing agent at a weight ratio of 10:1 to form a gel PDMS. Let the gel PDMS stand for a period of time to remove air bubbles, and then drop the gel PDMS onto the central part of the glass substrate and wait for the PDMS to spread naturally.

[0086] Step 4.2: Place the glass substrate on a heating stage and heat it to accelerate the curing of the gel-like PDMS, eventually forming a cured PDMS layer;

[0087] Step 4.3: Peel off the cured PDMS layer from the glass substrate, align it and cover the top of the PDMS reservoir, and use PDMS to cover and seal the PDMS reservoir to prevent the CuSO4 electrolyte in the PDMS reservoir from evaporating.

[0088] In this embodiment, the AAO film contains multiple parallel nanochannels, as shown in the schematic diagram. Figure 1 SEM characterization image reference Figure 2 Nanochannels have asymmetrical geometry, primarily manifested in the inconsistent pore sizes at their upper and lower ends, such as... Figure 2 As shown in a and b, the average apertures of the upper and lower end faces are 24 nm and 40 nm, respectively, the channel depth is 56 μm, and the cross-section is bullet-shaped. The SEM characterization images of the cross-section of the AAO thin film are shown below. Figure 2 As shown in c and d, the average spacing between two adjacent nanochannel pores is 60 nm.

[0089] In this embodiment, the current change of the AAO-based nanofluidic memristor in DC scan mode (0→20mV→0→-20mV→0) is as follows: Figure 3 As shown in the corresponding IV curve, the current changes with voltage exhibiting a self-crossing curve, which is typical bipolar memristor behavior in memristor devices. During the scan from the crossover point to the 20mV voltage range, the device's conductance gradually increases from low to high, and during the scan from the crossover point to the -20mV voltage range, the device's conductance gradually decreases from high to low. This result proves that the device exhibits the memristor effect.

[0090] Combination Figure 4 The nanofluidic memristor based on the AAO thin film maintains a stable memristor effect during 40 cyclic scan tests when the voltage scan range is 0→20mV→0→-20mV→0.

[0091] Combination Figure 5 The working principle of the nanofluidic memristor is that copper ions in the electrolyte are adsorbed or desorbed by the inner walls of the nanochannels in the nanochannel array, resulting in two states of high conductivity and low conductivity. Specifically, the inner walls of the nanochannels in the AAO film adsorb copper ions from the CuSO4 electrolyte, such as... Figure 5 As shown in ①, when a negative bias voltage is applied, under the influence of an external electric field, copper ions in the CuSO4 electrolyte migrate into the nanochannel array in the AAO film. The inner walls of the nanochannels continuously adsorb copper ions from the electrolyte until saturation is reached, as shown in ①. Figure 5As shown in ②, the copper ion flux in the nanochannels gradually increases, thus making the device a high-conductivity state. When a positive bias voltage is applied, the copper ions in the electrolyte gradually leave the nanochannel array along the direction of the external electric field, as shown in ②. Figure 5 As shown in ③, the copper ions adsorbed on the inner wall of the nanochannel are gradually desorbed. The copper ion flux in the nanochannel gradually decreases until the channel contains almost no copper ions, as shown in ③. Figure 5 As shown in ④, the device becomes a low-conductivity state.

[0092] The hysteresis effect in the IV curve occurs because when the applied voltage is changed in a specific step size, the redistribution of ions in the electrolyte according to the direction of the external electric field is slow, resulting in hysteresis. When the scan rate, i.e., the step size of the applied potential change, is low, the hysteresis loop of the IV curve is normal. However, when the scan rate is fast, the ions in the nanochannel do not have sufficient time to migrate and redistribute, making it difficult for the device conductivity to change, and the area of ​​the hysteresis loop in the IV curve shrinks.

[0093] Combination Figure 6 and Figure 7 The nanofluidic memristor provided in this embodiment can simulate the short-term plasticity of biological synapses. In the biological nervous system, synapses are responsible for connecting two neurons, and the short-term plasticity of synapses is the characteristic of synapses to briefly change their connection weights in order to transmit neuronal signals. This is a basic neural function of the brain for learning and memory.

[0094] Specifically, such as Figure 6 As shown in Figure a, when two consecutive triangular wave voltage pulses are applied to the device, with pulse voltage U = 0.5V and pulse duration T = 0.2ms, the absolute value of the current induced by the second voltage pulse is lower than the absolute value of the current induced by the first voltage pulse; for example... Figure 6 As shown in b, when two consecutive triangular wave pulses are applied to the device, U = -0.5V, T = 0.2ms, the absolute value of the current induced by the second voltage pulse is higher than that induced by the first voltage pulse; when the pulse interval ΔT between the two triangular wave voltage pulses gradually increases from 20μs to 40.96ms, as... Figure 6 As shown in Figure c, when U = 0.5V and T = 0.2ms, the difference between the absolute values ​​of the ion currents caused by the two pulses first decreases rapidly, and then gradually decreases; this is the PPD phenomenon. On the other hand, as... Figure 6As shown in Figure d, when U = -0.5V and T = 0.2ms, the difference between the absolute values ​​of the ion currents caused by the two pulses initially increases rapidly, reaching a peak at approximately 1.28ms, and then gradually decreases. This is the non-monotonic PPF phenomenon. The PPD and PPF phenomena are fundamental components of short-term synaptic plasticity. Retention time refers to the time required for the difference between the absolute values ​​of the ion currents caused by the two pulses to decay to 5% of its maximum value. Retention time in biological synapses is generally between ten and several hundred milliseconds. In this invention, the retention time of the nanofluidic memristor is 55.6ms during the PPF process and 19.5ms during the PPD process.

[0095] like Figure 7 As shown, when multiple consecutive triangular wave pulses are applied to the device, with N = 50 pulses, U = ±0.5V, T = 0.2ms, and ΔT = 50μs, the device's conductance increases or decreases accordingly with the application of the pulse signal. This demonstrates that the nanofluidic memristor based on the AAO thin film possesses short-term conductance tunability, namely STF and STD. Since STF and STD are components of the short-term plasticity of biological synapses, the nanofluidic memristor based on the AAO thin film exhibits short-term plasticity and has broad prospects in neuromorphic computing applications.

[0096] The energy consumption of the AAO thin film-based nanofluidic memristor provided in this embodiment can be estimated by the formula W = UIT / 2N′. When the pulse voltage U is 0.5V, the current I is 120μA, and the pulse duration T is 0.2ms, the number of parallel channels N′ is approximately 5.55 × 10⁻⁶. 7 Calculations using the formula show that the energy consumption of a single nanochannel is approximately 0.11 fJ / spike, which is the lowest energy consumption among all current nanofluidic memristors, even surpassing the energy consumption of 10–100 fJ during biological synapse operation. These results demonstrate the broad potential of AAO-based nanofluidic memristors in neuromorphic computing applications.

[0097] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A nanofluidic memristor based on AAO thin film, characterized in that, Includes a glass substrate, a PDMS reservoir, an AAO thin film, a CuSO4 electrolyte, a first copper electrode, and a second copper electrode; The glass substrate is the base plate of the memristor. A first copper electrode is disposed on the glass substrate. A PDMS reservoir is disposed on the first copper electrode. An AAO thin film is disposed in the PDMS reservoir and a CuSO4 electrolyte is contained therein. A second copper electrode is disposed on top of the PDMS reservoir. The first copper electrode, the AAO thin film, and the second copper electrode are connected in sequence. The AAO film contains multiple parallel nanochannels of a set size but with inconsistent pore sizes at both ends, forming a nanochannel array. The two ends of the nanochannel array are respectively connected to the first copper electrode and the second copper electrode. The copper ions in the CuSO4 electrolyte can undergo a solid-liquid reaction with the inner wall of the nanochannel in the AAO film, allowing the copper ions to be adsorbed onto the inner wall of the nanochannel. The first copper electrode and the second copper electrode are used to apply voltage to both ends of the nanochannel array in the AAO thin film. Under the drive of the electric field, copper ions in the CuSO4 electrolyte enter or leave the nanochannel array. Through the adsorption and desorption of copper ions by the inner wall of the nanochannel, the conductivity of the nanochannel array changes. This change is lagging behind the voltage change applied by the electrode, thereby generating the memristor effect and realizing a nanofluid memristor based on the AAO thin film. The thickness of the glass substrate ranges from 1 to 2 mm, the length ranges from 7 to 8 cm, and the width ranges from 2 to 3 cm. The PDMS storage tank is made of polydimethylsiloxane, i.e., PDMS material. The AAO film is made of anodized aluminum oxide, i.e., AAO material; In the AAO thin film, the density of nanochannels is 280 pores·μm. -2 The average distance between the centers of two adjacent nanochannels is 60 nm. The geometry of a single nanochannel is asymmetrical, with inconsistent pore sizes at both ends. The average pore sizes at both ends range from 20 to 30 nm and from 40 to 50 nm, respectively. The depth ranges from 50 to 60 μm, and the cross-section is bullet-shaped. The PDMS storage tank consists of one cubic tank with a length ranging from 5 to 20 mm, a width ranging from 5 to 15 mm, and a depth ranging from 1 to 3 mm. The first copper electrode and the second copper electrode each have a length range of 20-40 mm, a width range of 1-5 mm, and a thickness range of 0.1-0.2 mm, and are placed on the lower and upper ends of the PDMS storage tank, respectively.

2. A method for fabricating a nanofluidic memristor based on an AAO thin film as described in claim 1, characterized in that, Includes the following steps: Step 1: Place the first copper electrode in the center of the glass substrate, drop gel PDMS onto the front end of the first copper electrode, and heat the glass substrate to accelerate the curing of PDMS. Step 2: Use a punch to make holes in the cured PDMS layer to obtain a PDMS storage tank; Step 3: Transfer the AAO film, cut to the set size and containing the nanochannel array, into the PDMS reservoir, so that the lower surface of the AAO film is attached to the front end of the first copper electrode on the glass substrate, and then fill the PDMS reservoir with CuSO4 electrolyte. Step 4: Place the second copper electrode on the upper part of the PDMS storage tank, and then cover and seal the PDMS storage tank with PDMS. Step 1 involves placing a first copper electrode at the center of a glass substrate, drop-coating gel-like PDMS onto the front end of the first copper electrode, and heating the glass substrate to accelerate PDMS curing. The details are as follows: Step 1.1: Select the central position of the glass substrate, attach one end of the first copper electrode to the central position, and define this end as the front end and the other end as the rear end. The first copper electrode is horizontally attached to the glass substrate along the direction from the front end to the rear end. Step 1.2: Mix 0.5 mL of PDMS precursor and curing agent thoroughly at a weight ratio of 10:1 to form gel PDMS. Let the gel PDMS stand to remove air bubbles. Then, drop the gel PDMS onto the central part of the glass substrate and let the PDMS spread naturally to cover the front end of the first copper electrode near the center of the glass substrate. Step 1.3: Place the glass substrate on a heating stage and heat it at 120°C for 2 hours to accelerate the curing of the gel PDMS and finally form a cured PDMS layer. Step 4 involves placing a second copper electrode on top of the PDMS storage tank, and then covering and sealing the PDMS storage tank with PDMS, as detailed below: Step 4.1: Take another glass substrate, mix 0.5 mL of PDMS precursor and curing agent at a weight ratio of 10:1 to form a gel PDMS. Let the gel PDMS stand to remove air bubbles, and then drop the gel PDMS onto the center of the glass substrate and let the PDMS spread naturally. Step 4.2: Place the glass substrate on a heating stage and heat it to accelerate the curing of the gel-like PDMS, eventually forming a cured PDMS layer; Step 4.3: Peel off the cured PDMS layer from the glass substrate, align it and cover the top of the PDMS reservoir, and use PDMS to cover and seal the PDMS reservoir to prevent the CuSO4 electrolyte in the PDMS reservoir from evaporating.

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